Was at York Raceway over the weekend and axle problems developed. When doing a burnout passenger side wheel spun up, however drivers side stayed still. This happened a couple of times but has never happened before.
Was advised that the problem was to do with the Suregrip unit.
Since then we have removed the diff to investigate further and done a fair bit of research into the subject. Some people say that unit is not repairable but others say they have 'machined' the cones and added shims to restore its performance. However, they do not go into great detail about this process. Exactly what needs machining and by how much and where do the shims go? Does anyone know where I can get hold of some of these shims?
As cash is tight I would like to try and repair the unit but if push came to shove what would anyone suggest as a good replacement and supplier for this unit.
Diff has a 489 casing with a suregrip 'cone' type arrangement.
I have attached some pics of Suregrip in pieces, showing inside of cones and backside of gears. Both sides show wear/friction burns. Is this normal wear?
Thanks in advance for any assistance.
8 3/4 Suregrip - help needed
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Anonymous
cone type don't do standing burnouts well, have to be rolling
cones wear when 1 wheel can spin faster (a lot less grip) than the other so as the cones wear the spring tension isn't high enough causing them to spin/wear each other more,
you machine the faces to clean them up then shim the spring pack to restore tension
cones wear when 1 wheel can spin faster (a lot less grip) than the other so as the cones wear the spring tension isn't high enough causing them to spin/wear each other more,
you machine the faces to clean them up then shim the spring pack to restore tension
I had to do a cheap repair on a cone type sure grip a good few years ago. What happens is the cone bottoms out and can no longer grip on the tapered section. following an article I read in Mopar action, I machined about 30 thou off the bottom of the cones so they no longer bottomed out, and fitted springs from a 727 front drum inside the exsisting springs to increase tension. The article said you could get away without shimming it. It worked, and is still working years later. You could always try that.
“It’s good enough for Nancy”
Ok these two links show how to do the repair on a Borg warner unit used in Aussie mopars and Gen iii Firbird and camaro
i.e not your unit but the princepal is exactly the same in fact the BW unit is called a sure grip as well because it was made for chrysler
the cones and case ware
the cones and case are both cone shaped
the cones wedge into the case
if they get too small they are forced into into the case and hit the end
if you machine theface at the thin end of the cone down it fits further into the case and wedges in again agianst the sides before it bottoms out
take up space with shims between side gear and cone.
however the thinner your cones get due to machining the more likely they are to chew or twist off the splined end of the axle.
machining the cones takes the whole unit out of spec.
in theory both case and cones are a matched item and should be replaced together. i.e manual allways recommends service replacement of both at the same time. don't worry though 1000s of aussie valiants ford falcons and holden commodres are running around with machined cases and cones doing burnouts and drag racing with the 7 3/4 BW unit
It is like a thin spindly twig when compared to the 8 3/4
your unit should have two windows that show how far into the case the cone sits (they also allow gear oil in). a new one has a good 5-8 mm gap between the small end of the cone and the case end face. your will probably have 0
tis not the end of the world and can be fixed for a reduced but resonably long life.
the whole lot should be shimmed so it goes back together just.......
i.e case halfs should fit together cleanly. limited slip function will work then, corners and roundabouts manageble. shim it too tight and you may as well run a spool or weld the cones in
you can add in a little more and it will Not slip but ultimatly you will wear it out faster
http://mpikas.blogspot.com/2008/03/rebu ... -cone.html
www.geocities.com/luckyducky_96701/9-Bo ... 0Nov04.pdf
Dave
i.e not your unit but the princepal is exactly the same in fact the BW unit is called a sure grip as well because it was made for chrysler
the cones and case ware
the cones and case are both cone shaped
the cones wedge into the case
if they get too small they are forced into into the case and hit the end
if you machine theface at the thin end of the cone down it fits further into the case and wedges in again agianst the sides before it bottoms out
take up space with shims between side gear and cone.
however the thinner your cones get due to machining the more likely they are to chew or twist off the splined end of the axle.
machining the cones takes the whole unit out of spec.
in theory both case and cones are a matched item and should be replaced together. i.e manual allways recommends service replacement of both at the same time. don't worry though 1000s of aussie valiants ford falcons and holden commodres are running around with machined cases and cones doing burnouts and drag racing with the 7 3/4 BW unit
It is like a thin spindly twig when compared to the 8 3/4
your unit should have two windows that show how far into the case the cone sits (they also allow gear oil in). a new one has a good 5-8 mm gap between the small end of the cone and the case end face. your will probably have 0
tis not the end of the world and can be fixed for a reduced but resonably long life.
the whole lot should be shimmed so it goes back together just.......
i.e case halfs should fit together cleanly. limited slip function will work then, corners and roundabouts manageble. shim it too tight and you may as well run a spool or weld the cones in
you can add in a little more and it will Not slip but ultimatly you will wear it out faster
http://mpikas.blogspot.com/2008/03/rebu ... -cone.html
www.geocities.com/luckyducky_96701/9-Bo ... 0Nov04.pdf
Dave
The Greater Knapweed near the Mugwort by the Buckthorn tree is dying
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Chris&Adam
Thanks for your info and the good links guys.
Based on your info and other research we've done, think we are going to machine 50thou from the bottom of the cones, making the cones identical in height, and shim accordingly to bring back to 'stock'.
Can anyone recommend a suitable shim/s to use and/or supplier?
As can be seen in the photo below there is a lip from the very bottom edge of the cone to the face that has the splines in it of approx 10 thou. Does this need to be replicated when the cones are machined or would it be OK to have one totally flat surface?
Based on your info and other research we've done, think we are going to machine 50thou from the bottom of the cones, making the cones identical in height, and shim accordingly to bring back to 'stock'.
Can anyone recommend a suitable shim/s to use and/or supplier?
As can be seen in the photo below there is a lip from the very bottom edge of the cone to the face that has the splines in it of approx 10 thou. Does this need to be replicated when the cones are machined or would it be OK to have one totally flat surface?
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Chris&Adam
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Chris&Adam
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Chris&Adam